Address PR review: --fix-only, CLAUDE.md update, hash tests

- Use ruff check --fix-only instead of --fix || true so genuine ruff
  failures propagate while still tolerating unfixable violations
- Update CLAUDE.md: Pylint -> Ruff in lint command description
- Add 4 unit tests for MFCConfig.__hash__ (hash/eq contract, set/dict usage)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sbryngelson

CLAUDE.md

@@ -41,7 +41,7 @@ All commands run from the repo root via `./mfc.sh`.
 # Verification (pre-commit CI checks)
 ./mfc.sh precheck -j 8                     # Run all 5 lint checks (same as CI gate)
 ./mfc.sh format -j 8                       # Auto-format Fortran (.fpp/.f90) + Python
-./mfc.sh lint                              # Pylint + Python unit tests
+./mfc.sh lint                              # Ruff lint + Python unit tests
 ./mfc.sh spelling                          # Spell check
 
 # Module loading (HPC clusters only — must use `source`)

docs/documentation/contributing.md

@@ -715,14 +715,15 @@ Every push to a PR triggers CI. Understanding the pipeline helps you fix failure
 
 ### Lint Gate (runs first, blocks all other jobs)
 
-All four checks must pass before any builds start:
+All five checks must pass before any builds start:
 
 1. **Formatting** — `./mfc.sh format` (auto-handled by pre-commit hook)
 2. **Spelling** — `./mfc.sh spelling`
-3. **Toolchain lint** — `./mfc.sh lint` (Python code quality)
+3. **Toolchain lint** — `./mfc.sh lint` (ruff + Python unit tests)
 4. **Source lint** — checks for:
    - Raw `!$acc` or `!$omp` directives (must use Fypp GPU macros)
    - Double-precision intrinsics (`dsqrt`, `dexp`, `dble`, etc.)
+5. **Doc references** — validates documentation cross-references
 
 ### Build and Test Matrix
 

toolchain/bootstrap/format.sh

@@ -54,7 +54,7 @@ if [[ ${#PATHS[@]} -gt 0 ]]; then
     fi
 
     # Format Python files with ruff (auto-fix lint issues, then format)
-    ruff check --fix $SEARCH_PATHS > /dev/null || true
+    ruff check --fix-only $SEARCH_PATHS
     if ! ruff format $SEARCH_PATHS; then
         error "Formatting Python files failed."
         exit 1
@@ -70,7 +70,7 @@ else
     fi
 
     # Format Python files with ruff (auto-fix lint issues, then format)
-    ruff check --fix toolchain/ examples/ benchmarks/ > /dev/null || true
+    ruff check --fix-only toolchain/ examples/ benchmarks/
     if ! ruff format toolchain/ examples/ benchmarks/; then
         error "Formatting Python files failed."
         exit 1

toolchain/bootstrap/lint.sh

@@ -14,7 +14,7 @@ done
 
 log "(venv) Auto-fixing safe lint issues with$MAGENTA ruff$COLOR_RESET..."
 
-ruff check --fix toolchain/ examples/*/case.py benchmarks/*/case.py > /dev/null || true
+ruff check --fix-only toolchain/ examples/*/case.py benchmarks/*/case.py
 
 log "(venv) Running$MAGENTA ruff$COLOR_RESET on$MAGENTA MFC$COLOR_RESET's $MAGENTA""toolchain$COLOR_RESET."
 

toolchain/mfc/cli/test_cli.py

@@ -142,5 +142,42 @@ def test_docs_generates_markdown(self):
         self.assertIn("#", output)  # Should contain markdown headers
 
 
+class TestMFCConfigHash(unittest.TestCase):
+    """Test MFCConfig __hash__ / __eq__ contract."""
+
+    def test_equal_configs_same_hash(self):
+        """Equal MFCConfig objects must have the same hash."""
+        from ..state import MFCConfig
+
+        a = MFCConfig()
+        b = MFCConfig()
+        self.assertEqual(a, b)
+        self.assertEqual(hash(a), hash(b))
+
+    def test_different_configs_different_hash(self):
+        """Different MFCConfig objects should (likely) have different hashes."""
+        from ..state import MFCConfig
+
+        a = MFCConfig(debug=False)
+        b = MFCConfig(debug=True)
+        self.assertNotEqual(a, b)
+        self.assertNotEqual(hash(a), hash(b))
+
+    def test_usable_in_set(self):
+        """MFCConfig should be usable in a set."""
+        from ..state import MFCConfig
+
+        s = {MFCConfig(), MFCConfig(debug=True)}
+        self.assertEqual(len(s), 2)
+        self.assertIn(MFCConfig(), s)
+
+    def test_usable_as_dict_key(self):
+        """MFCConfig should be usable as a dict key."""
+        from ..state import MFCConfig
+
+        d = {MFCConfig(): "default", MFCConfig(debug=True): "debug"}
+        self.assertEqual(d[MFCConfig()], "default")
+
+
 if __name__ == "__main__":
     unittest.main()